Emulsion dispersion
Encyclopedia
An emulsion dispersion is thermoplastic
s or elastomer
s suspended
in a waterphase with help of emulsifiers.
in the presence of the other polymers; emulsion dispersion is a novel method of choice for the preparation of homogeneous
blends of thermoplastic
and elastomer
. In emulsion dispersion system the preparation of well-fined polymers droplets may be acquired by the use of water
as dispersing medium. The surfactant molecules adsorb on the surface
of emulsion by creating a dispersion of droplets, which reduces interfacial tension and retards particle flocculation during mixing. The molecules of surfactant have polar
and non-polar parts which act as an intermediary
to combine polar and non-polar polymers; the intermolecular interactions between the polar and the non-polar polymer segments resemble the macroscopic hydrocarbon-water interface. The idea of the emulsion dispersion inspired by emulsification of liquid natural rubber (LNR)
, from particle size analysis and optical microscopy results showed that the droplet size of emulsion of LNR with higher molecular weight is greater than that of the lower molecular weight. Emulsion dispersion was able to produce homogeneous low density polyethylene
(LDPE)/LNR blends and nylon 6
/LNR blends. Results of differential scanning calorimetry
(DSC) thermogram indicated a single glass transition temperature (Tg) showed that the blends were compatible and Scanning Electron Microscopy (SEM) micrograph
showed no phase separation between blend components. In addition, exfoliated HDPE/LNR/montmorillonite
nanocomposites were successfully achieved by using emulsion dispersion technique as well.
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
s or elastomer
Elastomer
An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
s suspended
Suspension (chemistry)
In chemistry, a suspension is a heterogeneous fluid containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometer. The internal phase is dispersed throughout the external phase through mechanical agitation, with the use of certain...
in a waterphase with help of emulsifiers.
Preparation
Emulsions are thermodynamically unstable liquid/liquid dispersions that are stabilized, in general, by surfactants. Surfactants are usually added to emulsion systems, assembling in the interface of the emulsion droplets, thus providing a protective membrane that prevents the droplets from flocculating or coalescing and thus enhancing the droplets formation and stability. Emulsion dispersion is not about reactor blends for which one polymer is polymerized from its monomerMonomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
in the presence of the other polymers; emulsion dispersion is a novel method of choice for the preparation of homogeneous
Homogeneous (chemistry)
A substance that is uniform in composition is a definition of homogeneous. This is in contrast to a substance that is heterogeneous.The definition of homogeneous strongly depends on the context used. In Chemistry, a homogeneous suspension of material means that when dividing the volume in half, the...
blends of thermoplastic
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
and elastomer
Elastomer
An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
. In emulsion dispersion system the preparation of well-fined polymers droplets may be acquired by the use of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
as dispersing medium. The surfactant molecules adsorb on the surface
Surface
In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...
of emulsion by creating a dispersion of droplets, which reduces interfacial tension and retards particle flocculation during mixing. The molecules of surfactant have polar
Chemical polarity
In chemistry, polarity refers to a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds. Molecular polarity is dependent on the difference in...
and non-polar parts which act as an intermediary
Intermediary
An intermediary is a third party that offers intermediation services between two trading parties. The intermediary acts as a conduit for goods or services offered by a supplier to a consumer...
to combine polar and non-polar polymers; the intermolecular interactions between the polar and the non-polar polymer segments resemble the macroscopic hydrocarbon-water interface. The idea of the emulsion dispersion inspired by emulsification of liquid natural rubber (LNR)
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
, from particle size analysis and optical microscopy results showed that the droplet size of emulsion of LNR with higher molecular weight is greater than that of the lower molecular weight. Emulsion dispersion was able to produce homogeneous low density polyethylene
Low density polyethylene
Low-density polyethylene is a thermoplastic made from petroleum. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries using a high pressure process via free radical polymerization. Its manufacture employs the same method today. LDPE is commonly recycled and has...
(LDPE)/LNR blends and nylon 6
Nylon 6
Nylon 6 or polycaprolactam is a polymer developed by Paul Schlack at IG Farben to reproduce the properties of nylon 6,6 without violating the patent on its production. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization. This makes...
/LNR blends. Results of differential scanning calorimetry
Differential scanning calorimetry
Differential scanning calorimetry or DSC is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature...
(DSC) thermogram indicated a single glass transition temperature (Tg) showed that the blends were compatible and Scanning Electron Microscopy (SEM) micrograph
Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an item.Micrographs are widely used in all fields of microscopy.-Photomicrograph:...
showed no phase separation between blend components. In addition, exfoliated HDPE/LNR/montmorillonite
Montmorillonite
Montmorillonite is a very soft phyllosilicate group of minerals that typically form in microscopic crystals, forming a clay. It is named after Montmorillon in France. Montmorillonite, a member of the smectite family, is a 2:1 clay, meaning that it has 2 tetrahedral sheets sandwiching a central...
nanocomposites were successfully achieved by using emulsion dispersion technique as well.
External links
- http://www.fkkksa.utm.my/mpj/images/03rusli.pdf
- http://pkukmweb.ukm.my/~jsm/english_journals/vol36num2_2007/vol36num2_07page183-188.html
- http://www.springerlink.com/content/941k0h10p7175hh4/?p=9df3b86ddbc24b9f87ef7525342226bf&pi=2
- http://www.springerlink.com/content/941k0h10p7175hh4/fulltext.pdf